The invention relates generally to product conveyance in multiple function integrated machinery. One specific aspect relates to an apparatus and method for transporting products in an indexing rotary manner to and from the operating stations of an integrated machine. Without intending to be a limitation thereof, the invention is described as used and implemented in an integrated machine with four operation stations.
In machines of this type, the need to accurately align the products with the mechanism at each machine operating station, imposes a severe requirement on the accuracy and repeatability of the indexing drive system. Further, to successfully execute the machine functions at the operating stations, the product carrier must be held in place against forces exerted on the products by the station mechanisms. In the past, these requirements have been met by indexing devices which relied on positive stops. Examples include paddle torque motors and shot pin locks. Such devices have the adverse characteristic of degraded performance over time due to mechanical wear. Furthermore, if a drive were designed relying only on a torque motor to hold the product carrier in place, the overall machine cycle time would be increased by the time needed to reset the torque motor to a start position in preparation for the next index.
An index drive is disclosed incorporating an indexing mechanism which achieves the desired accuracy, repeatability and self-locking qualities without resort to positive stops. The operation of this mechanism is further enhanced by the disclosed method of controlling the indexer driving motor so as to avoid degradation of the overall machine cycle time.